Lesson 1
A very rare blue
Cyanophores (say "sy-AN-o-fors") are skin cells that hold blue pigment. They are very rare. Scientists have found them in only a few kinds of fish.
The best-known one is the mandarin fish, a small fish from coral reefs in the Pacific Ocean. It is covered in swirly blue and orange patterns, like a painting. In the 1990s, scientists looked at its skin under a microscope and found blue cells shaped like stars.
Each cyanophore has arms that reach out through the skin, filled with tiny blue grains.
Lesson 2
Blue the hard way
Most blue animals do not have blue pigment at all! A blue jay feather or a blue butterfly wing has tiny patterns that bounce back only blue light. That is called structural color.
Cyanophores are different. Their grains hold real blue pigment. When white light shines on them, the pigment soaks up the other colors and sends blue back to your eyes. Scientists are still studying what this blue pigment is made of.
Try thisScroll up to the 3D model and press Shine light to see white light go in and blue light come out.
Wow!If you crush a blue jay feather, the blue goes away, because the tiny patterns get broken. Blue pigment, like the kind in cyanophores, would stay blue.